WASTE TO ENERGY

WASTE TO ENERGY W2E

Group Members

Saira Sehzadi (11-Env-06)

Maryem Javed (11-Env-73)

Sundas khursheed (11-Env-82)

INTRODUCTION

Need for waste to energy

The amount of solid waste generated each year has been increasing much faster than population growth.

Growing demand of energy is also increases.

Today, we face numerous environmental & economic challenges:

•Population growth and associate waste disposal needs•Global Warming•Dependence on fossil fuels

There is a common solution for all of these challenges.

Energy-from-Waste (EfW) provides:•Safe, economic waste disposal•Greenhouse gas reduction•Renewable energy

In waste management there are several methods:

Best method

Waste to Energy

Waste-To-Energy (WTE) technologies recover the energy from the waste. Waste can include:•Residential•Industrial• Commercial• Institutional• Construction and demolition

All of the above included as â municipal solid ��waste(MSW).• Agriculture

Waste-to-Energy

Municipal Solid Waste 1 ton

Power: up to 750 kWhAsh: 10% of original volume

CASE STUDY

European nations rely on waste-to-energy as the preferred method of waste disposal.

According to the Confederation of European Waste-to-Energy Plants (CEWEP), Europe currently treats 50 million ton of wastes at waste-to-energy plants each year, generating an amount of energy that can supply electricity for 27 million people or heat for 13 million people

TYPES OF ENERGY FROM WASTE

Thermal conversion:•Combustion•Gasification •Pyrolysis

Biochemical conversion•Anaerobic Digestion

Landfill Gas

TECHNOLOGY SELECTION CONSIDERATIONS

ENVIRONMENT

ENERGY

• CO2 Control

• DXNs Control• Emission Control• Landfill Control

• Cost Control• Profit• Growth

• Energy Recovery• High Efficiency• Utilization / Sale

Waste characteristics

• waste type• waste quality• waste contents

Technologies Overview

Thermal Conversion: Gasification

• Gasification is a process that uses high temperatures (without combustion) to decompose materials to produce synthetic gas. Temperature > 1300oF

• It takes place in the presence of limited amounts of oxygen

Thermal Conversion: Pyrolysis

• It is defined as the thermal decomposition of carbon-based materials in an oxygen-deficient atmosphere using heat to produce syngas.No air or oxygen is present and no direct burning takes place. The process is endothermic.

• Lower temperature than gasification (750 – 1500oF)

Syngas

Main product of gasification and

pyrolysis

Caloriific Value: approx. 13

MJ/kg, half of natural gas

It is used as a fuel to generate

electricity or steam

It is used to produce

synthetic diesel

Syngas

Thermal Conversion: Combustion

• Thermal conversion of a feedstock utilizing excess air or oxygen as oxidant to generate heat.

Biochemical conversion: Anaerobic Digestion

• “An anaerobic digester is an air tight, oxygen‐free container that is fed an organic material, such as animal manure or food scraps.

• A biological process occurs to this mixture to produce methane gas, commonly known as biogas, along with an odor‐reduced effluent. Microbes break down manure into biogas and a nutrient‐rich effluent.”

Anaerobic Digestion

Benefits Of AD

Reduce Environmental Impacts:• Odors• Pathogens • Greenhouse gases

Create value‐added products:• renewable energy (biogas)(heat, electricity, CHP, compressed gas for vehicles, pipeline gas)

• fertilizer• fibers(bedding, mulch, hydroseeding, potting soil amendment)

Landfill Gas

• Landfill gas (LFG)-to-energy is a form of anaerobic digestion and is a biological treatment method of WTE.

• LFG is created during the decomposition of organic substances in MSW when it is dumped, compacted, and covered .

• LFG-to-energy as a method of WTE conversion does not require new technology, but instead depends on harnessing the methane (CH4), carbon dioxide (CO2), and nitrogen (N2) that is and always has been created by MSW

• LFG-to-energy is economically attractive because unlike other WTE conversion technologies, it does not require a new facility. Gas can be collected from an existing landfill and either used as is, upgraded to a higher quality gas, or converted to energy through combustion, a gas turbine, or a steam turbine

Landfill Gas Process Flows

Waste-to-Energy Plant

Criteria For Selection of WTE

Criteria for Selection of WTE